Identification device for motor vehicle

ABSTRACT

A device for identifying a motor vehicle comprising an identification unit carried by the user, a central onboard console ( 1 ) for verifying the user&#39;s identification data via an electromagnetic wave communication, through a resonant circuit having at least one tuning capacitor ( 13 ) and at least one coil transmitting/receiving ( 12 ) identification data; and at least one support module ( 10 ) comprising said transmission/reception coil and fitted at the vehicle door; said support module and said central console are spaced apart from each other and connected by electrical connection means; wherein the resonant circuit tuning capacitor is fitted in said support module ( 10 ) to limit parasitic radiation from the resonant circuit.

The invention relates to an identification device, in particular of the“hands-free” type, for automobile vehicles.

In order to better appreciate the invention, it is helpful to present aknown identification system and its disadvantages. FIG. 1 is asimplified diagram of an identification device comprising a centralelectrical console 1, generally located in the passenger compartment ofthe vehicle, and a support module 10 containing electronic components 11and 12 that enable the central console 1 to communicate with anidentification unit (not shown) such as a badge carried by a user. Thesupport module 10 is mounted in a door handle or trunk of the vehicleand will be described in more detail below.

For reasons of clarity, only one support module 10 with its electriccomponents 11 and 12 has been shown, but it is of course possible toequip every handle of the vehicle with such a module 10 that isconnected to the single central electrical console 1.

As shown in FIG. 1, the central console 1 and the electric components 11and 12 are connected by connection means 20, 22, 23, 24 generallypressed against the walls of the vehicle's passenger compartment.

Classically, the electronic components 11 and 12 in the support module10 comprise an approach sensor 11 and a transmission/reception coil 12.

A microcontroller 3, an amplifier stage 5, a resistor 2, a tuningcapacitor 13, a ground connection 4 and a battery connection 6 arefitted in the central console 1.

The microcontroller 3 generates identification data and verifies theauthenticity of the identification data emitted by the badge.Hereinafter it will be referred to as the verification microcontroller.

The resistor 2, the tuning capacitor 13 and the transmission/receptioncoil 12 form a resonant circuit.

Classically, the resistor 2 and the tuning capacitor 13 of the circuitare mounted in the central console 1. The transmission/reception coil ismounted in the support module 10 such that its emission/reception fieldis localized at the handles of the vehicle.

The capacitor 13 is usually called a tuning capacitor since itscapacitance value is defined such that the resonance frequency of thetransmission/reception coil 12 is equal to the resonance frequency ofthe coil fitted in the badge carried by the user.

This tuning capacitor 13 ensures a high quality factor of the resonantcircuit, which increases the emission/reception range of the coil 12.

The tuning capacitor has a capacitance of about ten nanoFarads to ensurea high tension, often about a hundred Volts, at its terminals at theworking frequency.

Owing to the high tension on the electrical link between the console 1and the module 10, and its length, parasitic radiation is generatedwhich perturbs the field generated by the coil 12 and other vehiclesystems.

The resonance frequency of the badge and the transmission/reception coil12 must match in order for the badge to be able to receive the data sentby the coil 12. However the electrical link 20 induces an additionalcapacitance, parasitic, which modifies the operating frequency of thecoil 12. Moreover, this parasitic capacitance has a value that dependson the geometry of the vehicle and is therefore difficult to control.

One known method of overcoming these disadvantages is to make the linkbetween the support module 10 and the central console 1 using a twisted,screened cable 20.

However, this type of cable 20 is bulky, which is a disadvantage in viewof the limited mounting space in the door. In a vehicle, numerousfunctions are performed by electric activators, and the electricalwiring must occupy as little space as possible in order to maximize thepassenger compartment.

Moreover, a cable 20 of twisted, screened type costs much more than asimple twisted cable.

For these reasons, the object of the invention is to build anidentification device including electrical links of small diameter, fewin number and of low cost between the central console 1 and the supportmodule 10.

For this purpose, the object of the invention is an identificationdevice as defined in claim 1.

The device according to the invention can also have one or more of thefollowing characteristics:

-   -   the resonant circuit includes an adjusting capacitor, fitted in        the central console, used for fine adjustment of the resonant        circuit resonance frequency, to be able to take account of the        geometry of each type of vehicle;    -   the central console includes a verification microcontroller to        verify said identification data, and the support module includes        an approach sensor and an amplifier stage connected to the        resonant circuit, said approach sensor including at least one        electrode and a processing microcontroller that sends a        triggering signal to said verification microcontroller, said        processing microcontroller being connected to said verification        microcontroller to also manage the sending of said        identification data, by multiplexing on a common serial link,        thereby reducing the number of wires between the support module        and the central console;    -   the central console includes a verification microcontroller to        verify said identification data, and the support module includes        an additional microcontroller, an amplifier stage and the        resonant circuit connected together in series, said additional        microcontroller being connected to said verification        microcontroller to manage the sending of said identification        data, by multiplexing on said common serial link, thereby        reducing the number of wires between the support module and the        central console.    -   the device includes at least one closing control means, acting        on a vehicle door and fitted on the support module, said control        means including at least one electrode and a processing        microcontroller that sends a door locking command signal;    -   the processing microcontroller that sends a triggering signal is        connected to said electrode to also manage the sending of a        locking command signal, by multiplexing on said common serial        link, thereby reducing the number of wires between the support        module and the central console;    -   the closing control means is a tactile sensor;    -   the closing control means include a manually operated switch;    -   the support module and the central console are connected by only        one ground connection serving as ground for all the electronic        components in said module, thereby reducing the number of wires        between the support module and the central console;    -   the support module and the central console are connected by only        one power supply connection serving as power supply for all the        electronic components in said module, thereby reducing the        number of wires between the support module and the central        console.

The invention will be better understood on reading the detaileddescription below of embodiments, which are non-limitative and takenonly as examples, with reference to the attached drawings of which:

FIG. 1 is a schematic diagram of an identification device according tothe prior art (described in the preface);

FIG. 2 is a schematic diagram of an identification device according to afirst embodiment of the invention;

FIG. 3 is a schematic diagram of an identification device according to asecond embodiment of the invention.

FIG. 2 shows an identification device according to a first embodiment ofthe invention. The items identical to those in FIG. 1 carry the samereference numbers.

However, according to the invention, the tuning capacitor 13 is fittedin the support module 10 rather than in the central console 1.

Consequently, the tension carried by the electrical link 21 between thecentral console 1 and the support module 10 is only about ten Volts, soit generates much less parasitic radiation.

The tension is high only on the link between the tuning capacitor 13 andthe coil 12, but the field generated is negligible since the tuningcapacitor 13 and the coil 12 are juxtaposed on the electronic board ofthe support module.

Consequently, thanks to the invention, it is possible to use anunscreened, inexpensive twisted cable 21 to connect the central console1 and the support module 10, bringing advantages in terms of cost andspace of the electrical links in the vehicle.

Advantageously, an adjusting capacitor 4 of a few tens of picoFarads ismounted downstream of the resistor 2. This adjusting capacitor 4provides for fine tuning of the resonance frequency, to take account ofthe geometry of the vehicle in which the identification device isinstalled, given that the generated magnetic field is affected by thequantity and proximity of bodywork metal and the vehicle handle.

This adjusting capacitor has a low capacitance such that its outputtension is only about ten Volts, so despite the presence of thisadjusting capacitor 4 the twisted cable 21 does not need to be screened.

Consequently, the fitting of the identification device is easier sincethe adjustment of the resonance frequency is made only once in thecentral console for all the doors.

Moreover, the same identification device can be easily fitted ondifferent types of vehicle. The operating frequency of the device isthen adjusted for each type of vehicle to take account of its geometryand the required resonance frequency. Thanks to the use of thisadjusting capacitor, it becomes much easier to standardizeidentification devices.

A secondary advantage of the adjusting capacitor is that providesprotection against short-circuits.

Moreover, as seen in FIG. 1, the approach sensor 11, mounted in thesupport module, comprises one or more electrodes 15 and amicrocontroller 14 for processing and sending a triggering signal.

This processing microcontroller 14 is connected to the central console 1by three electrical links: a link to ground 24, a link to the powersupply 23 and a transmission link 22 for a triggering signal to themicrocontroller 3 verifying the identification data.

Advantageously, according to the invention, the ground of the processingmicrocontroller 14 is connected by a wire 25 to the ground wire oftwisted cable 21. In this manner, the approach sensor 11 and thetransmission/reception coil 12 use the same ground link, which thereforereduces the number of wires between the central console 1 and thesupport module 10.

A second embodiment of the invention is shown in FIG. 3. In thisembodiment, the amplifier stage 5 and the resistor 2 have been fitted inthe support module 10, in series with the tuning capacitor 13 and thetransmission/reception coil 12.

Moreover, an additional microcontroller 16 manages the processing andsending and/or reception of the identification data emitted and/orreceived by the coil 12.

Consequently, the electrical link 21 for transmission of theidentification data between the console 1 and the support module 10 iseliminated, which saves space and reduces the cost.

Moreover, the data transmission link 32 connecting the additionalmicrocontroller 16 to the verification microcontroller 3 carries noalternating signal, so it does not need to be twisted, which also savesspace and money.

In this case, the additional microcontroller 16 manages the transmissionof the identification data. However, it would also be possible for theadditional microcontroller 16 to generate the identification data andsend it both to the amplifier stage 5 and to the verificationmicrocontroller 3. In this case, the identification data emitted by thebadge are still authenticated by the verification microcontroller 3which authorizes unlocking of the opening.

In a variant of the invention, the processing microcontroller 14 of theapproach sensor replaces the additional microcontroller.

In this variant, the processing microcontroller 14 advantageouslyprocesses the triggering signal and manages at the same time, by meansof multiplexing, the sending and/or receiving of the triggering signaland the identification data on a single transmission link 32.

Advantageously, the support module 10 also includes door closing controlmeans, such as a tactile sensor or a manually operated switch.

A tactile sensor generally comprises an electrode 40 and amicrocontroller that processes and sends a door locking signal.

According to the invention, the processing microcontroller 14 of theapproach sensor 11 advantageously also manages the processing andsending and/or reception of a locking signal on the transmission link32.

Moreover, according to the invention, a power supply link 33 connectsthe central console 1 to the processing microcontroller 14. This powersupply 33 feeds the closing control means and the approach sensor 11.

Also advantageously, a ground link 34 connects the central console 1 tothe processing microcontroller 14. This ground 34 provides the groundfor the transmission/reception coil 12, the approach sensor 11 and theclosing control means.

In this manner, a single power supply 33, a single ground 34 and asingle data transmission link 32 connect the central console 1 and eachsupport module 10.

The connections to ground and to the battery can also be via anelectrical harness of the vehicle and serve each of the electroniccomponents of the vehicle individually. In this case, the variants ofthe invention described above are also feasible.

Consequently, the invention considerably reduces the size of theelectrical links.

Moreover, the number of electrical connections is reduced, whichincreases the reliability of the identification device, since electricalconnections are a common cause of faults.

In addition, the support module can be easily mounted to ensure maximumcomfort for the user.

1. Device for identifying an automobile vehicle, comprising: anidentification unit carried by a user; a central onboard console (1) forverifying a user's identification data via electromagnetic wavecommunication through a resonant circuit (2, 12, 13) having at least onetuning capacitor (13) and at least one transmission/reception coil (12)transmitting/receiving said identification data; and at least onesupport module (10) comprising said transmission/reception coil (12) andfitted at a vehicle door; said central onboard console (1) being locatedin a passenger compartment of the vehicle in a location spaced from saidvehicle door; said support module (10) and said central onboard console(1) being spaced apart from each other and connected by electricalconnection means (20-24; 32-34), wherein said resonant circuit tuningcapacitor (13) is fitted together with said transmission/reception coil(12) on an electronic board in said support module (10) to limitparasitic radiation from said resonant circuit.
 2. The identificationdevice according to claim 1, wherein said resonant circuit includes anadjusting capacitor (4), fitted in said central onboard console (1),used for fine adjustment of the resonant circuit resonance frequency, tobe able to take account of the geometry of each type of vehicle.
 3. Adevice for identifying an automobile vehicle, comprising: anidentification unit carried by a user; a central onboard console (1) forverifying a user's identification data via electromagnetic wavecommunication through a resonant circuit (2, 12, 13) having at least onetuning capacitor (13) and at least one transmission/reception coil (12)transmitting/receiving said identification data; and at least onesupport module (10) comprising said transmission/reception coil (12) andfitted at a vehicle door; said central onboard console (1) being locatedin a passenger compartment of the vehicle in a location spaced from saidvehicle door; said support module (10) and said central onboard console(1) being spaced apart from each other and connected by electricalconnection means (20-24; 32-34), wherein said resonant circuit tuningcapacitor (13) is fitted together with said transmission/reception coil(12) on an electronic board in said support module (10) to limitparasitic radiation from said resonant circuit, wherein said centralonboard console (1) includes a verification microcontroller (3) toverify said identification data, and wherein said support module (10)includes an additional microcontroller (14), an amplifier stage (5) andsaid resonant circuit (2, 12, 13) connected together in series, saidadditional microcontroller (14) being connected to said verificationmicrocontroller (3) to manage the sending of said identification data,by multiplexing on a common serial link (32), thereby reducing thenumber of wires between said support module (10) and said centralonboard console (1).
 4. A device for identifying an automobile vehicle,comprising: an identification unit carried by a user; a central onboardconsole (1) for verifying a user's identification data viaelectromagnetic wave communication through a resonant circuit (2, 12,13) having at least one tuning capacitor (13) and at least onetransmission/reception coil (12) transmitting/receiving saididentification data; and at least one support module (10) comprisingsaid transmission/reception coil (12) and fitted at a vehicle door; saidcentral onboard console (1) being located in a passenger compartment ofthe vehicle in a location spaced from said vehicle door; said supportmodule (10) and said central onboard console (1) being spaced apart fromeach other and connected by electrical connection means (20-24; 32-34),wherein said resonant circuit tuning capacitor (13) is fitted togetherwith said transmission/reception coil (12) on an electronic board insaid support module (10) to limit parasitic radiation from said resonantcircuit, wherein said central onboard console (1) includes averification microcontroller (3) to verify said identification data, andwherein said support module (10) includes an approach sensor (11) and anamplifier stage (5) connected to said resonant circuit (2, 12, 13), saidapproach sensor (11) comprising at least one electrode (15) and aprocessing microcontroller (14) that sends a triggering signal to saidverification microcontroller, said processing microcontroller (14) beingconnected to said verification microcontroller (3) to also manage thesending of said identification data, by multiplexing on a common seriallink (32), thereby reducing the number of wires between said supportmodule (10) and said central onboard console (1).
 5. The identificationdevice according to claim 4, wherein at least one closing control means(14, 40), acting on a vehicle door, is fitted on said support module(10), said control means comprising at least one electrode (40) and aprocessing microcontroller that processes and sends a door lockingcommand signal.
 6. The identification device according to claim 5,wherein said additional microcontroller or said processingmicrocontroller (14) that sends a triggering signal is connected to saidelectrode (40) to also manage the sending of a locking command signal,by multiplexing on said common serial link (32), thereby reducing thenumber of wires between said support module (10) and said centralonboard console (1).
 7. The identification device according to claim 5,wherein said closing control means (40, 14) is a tactile sensor.
 8. Theidentification device according to claim 5, wherein said closing controlmeans (40, 14) includes a manually operated switch.
 9. Theidentification device according to claim 3, wherein said support module(10) and said central onboard console (1) are connected by only oneground link (34) providing the ground for all the electronic components(40, 12, 11) in said module (10), thereby reducing the number of wiresbetween said support module (10) and said central onboard console (1).10. The identification device according to claim 5, said support module(10) and said central onboard console (1) are connected by only onepower supply link providing the power supply for all the electroniccomponents (40, 11) in said module (10), thereby reducing the number ofwires between said support module (10) and said central onboard console(1).
 11. The identification device according to claim 3, wherein atleast one closing control means (14, 40), acting on a vehicle door, isfitted on said support module (10), said control means comprising atleast one electrode (40) and a processing microcontroller that processesand sends a door locking command signal.
 12. The identification deviceaccording to claim 11, wherein said additional microcontroller or saidprocessing microcontroller (14) that sends a triggering signal isconnected to said electrode (40) to also manage the sending of a lockingcommand signal, by multiplexing on said common serial link (32), therebyreducing the number of wires between said support module (10) and saidcentral onboard console (1).
 13. The identification device according toclaim 12, wherein said closing control means (40, 14) is a tactilesensor.
 14. The identification device according to claim 12, whereinsaid closing control means (40, 14) includes a manually operated switch.15. The identification device according to claim 11, said support module(10) and said central onboard console (1) are connected by only onepower supply link providing the power supply for all the electroniccomponents (40, 11) in said module (10), thereby reducing the number ofwires between said support module (10) and said central onboard console(1).
 16. The identification device according to claim 11, furthercomprising an adjusting capacitor (4) mounted downstream of a resistor(2) in said central onboard console (1) for fine tuning of a resonancefrequency whereby said adjusting capacitor (4) takes into accountgeometry of said vehicle and for protection against short-circuit.